Development and Optimization of Resveratrol-Loaded NLCs via Low-Energy Methods: A Promising Alternative to Conventional High-Energy or Solvent-Based Techniques

High-energy methods dominate the development of lipid nanoparticles but often require specialized equipment that increases production costs. Low-energy approaches, particularly those free of organic solvents, offer a promising alternative. This study aimed to obtain nanostructured lipid carriers (NLCs) using a solvent-free, low-energy process combining microemulsification and phase inversion. Cetearyl alcohol and PEG-40 hydrogenated castor oil were selected as the solid lipid and surfactant, respectively; the formulation and process were optimized through a Box–Behnken Design. Incorporation of the ionic surfactant extended colloidal stability, while the poloxamer in the aqueous phase enhanced steric stabilization. Resveratrol was efficiently encapsulated (E.E. = 98%), contributing to reduced particle size (291 nm), improved homogeneity (PDI = 0.25), and positive surface charge (+43 mV). Scale-up yielded stable particles carrying resveratrol with a mean size of 507 nm, PDI = 0.24, and ZP = +52 mV. The optimized formulation remained stable for 90 days at 8 °C. In vitro release demonstrated a sustained and controlled release profile, with significantly lower resveratrol release compared to the free compound. Thermal analysis confirmed drug incorporation within the lipid matrix, while transmission electron microscopy (TEM) revealed spherical particles (~200 nm) and SAXS indicated a nanostructure of ~50 nm. Overall, this study demonstrates that solvent-free, low-energy processing can produce stable and scalable NLC formulations, successfully encapsulating resveratrol with favorable physicochemical properties and controlled release behavior. These findings highlight a simple, cost-effective strategy for developing lipid-based nanocarriers with potential applications in drug delivery.